The PTS EPM1-S AEG magazine, made with the same technology as the PTS EPM1, is a 20R length short M4 magazine that holds an incredible 170 round bb capacity and offers the same reliability that all PTS magazines have long been famous for. It is compatible with most Airsoft AR-15 M4 AEGs including Tokyo Marui, KWA, G&P, VFC, including the HK416, PTS PDR-C, PTS ERG series, PTS Masada AEG, the AMOEBA AM Variants, and many more